Dental chair



March 9, 1965 J. 1.. NAUGHTON 3,172,699

DENTAL CHAIR Original Filed Dec. 10, 1959 4 Sheets-Sheet l //v VEN TOR JOHN L. NAUGHTON JM MM A T TORNE vs March 9, 1965 J. NAUGHTON 3,172,699

DENTAL CHAIR Original Filed Dec. 10, 1959 4 Sheets-Sheet 2 0 94; I08 /07 m4 i /N' VE N TOR 28 3 FY95 JOHN L. NAUGHTON m I" 7 EV 42 I09 2 'l 43 Fri 4 MW A TT'ORNE Y5 March 9, 1965 J. L. NAUGHTON DENTAL CHAIR 4 Sheets-Sheet 5 Original Filed Dec. 10, 1959 Fig. I

N w H 6 u WA N L Arromvsvs March 9, 1/965 J. L. NAUGHTON 3,172,699

I DENTAL CHAIR L Original Filed Dec. 10/, 1959 4 Sheets-Sheet 4 NVENTOR Joy/v L. NAUGHTON ATTORNEYS United States Patent 3,172,699 DENTAL CHAIR John L. Naughton, Des Moines, Iowa, assiguor to Den- Tal-Ez Chair Mfg. Co., Des Moines, Iowa, 21 corporation of Iowa Continuation of application Ser. No. 858,695, Dec. 10, 1959. This application July 1, 1963, Ser. No. 292,803 4 Claims. (Cl. 297327) This application is a continuation of application Serial No. 858,695 filed December 10, 1959.

This invention relates generally to adjustable chairs and more particularly to chairs adapted for use by dentists and the like.

Dental chairs, generally, have remained virtually unchanged for several decades. Several objections to the present day dental chair include the lack of comfort for the patient, the lack of Working convenience for the dentist, and the lack of quick and easy maneuverability of the various components of the chair for ready adjustment of the chair to accommodate the posture of the particular atient. P It is an object of this invention, therefore, to provide an improved dental chair. A further object of this invention is to provide a new and novel type of dental chair of a construction for comfortably supporting a patient.

Another object of this invention is to provide a dental chair having a contoured seat and leg surface and a back rest of an improved construction whereby the patient is completely and comfortably supported from head to foot while enabling the dentist to work closely adjacent the patient in an eflicient position.

Yet another object of this invention is the provision of a dental chair having two pivotally movable units for supporting the upper and lower halves of a patient, and including apparatus for comfortably supporting the arms substantially parallel to the legs of the patient irrespective of the relative positions of the units and further wherein the arm supporting apparatus can be manipulated to provide easy ingress and egress for the patient from the side of the chair. h

A further object of this invention is to provide a dental chair capable of moving the upper and lower extremities of a patient relative to each other, either independently or simultaneously.

Another object of this invention is the provision of a dental chair having two frames covered in an attractive manner, and wherein the mechanism for moving the frames relative to each other is mounted within the frames so as not to detract from the overall appearance of the chair.

Yet another object of this invention is the provision of a dental chair having a pair of pivotally connected frames adapted to completely support a patient from head to foot, and which frames are adjustably movable relative to each other independently and simultaneously by control means centralized and mounted on one of the frames for convenient operation by the dentist, and further wherein movement to any adjusted position is by progressive increments.

These and other objects of this invention will become readily apparent from the following description of the invention when taken in connection with the following drawings, wherein:

FIG. 1 is a perspective view of the dental chair of this invention;

FIG.'2 is a fragmentary front elevational view of the dental chair of FIG. 1, with parts broken away and other parts shown in section;

FIG. 3 is a perspective view of the dental chair, similar to FIG. 1, having the upholstery removed and showing the internal framework and the operating mechanism therefor;

FIG. 4 is a fragmentary, front elevational view similar to FIG. 2, having the upholstery removed and showing the internal framework, with some parts broken away and with other parts shown in changed positions;

FIG. 5 is a schematic drawing showing the electric control circuit for the chair;

FIG. 6 is a fragmentary rear elevational view of the dental chair;

FIG. 7 is a view similar to FIG. 6 with the upholstery removed and with some parts broken away;

FIG. 8 is a reduced side elevational view of the chair in one position;

FIG. 9 is a view similar to FIG. 8 showing the chair in a changed position relative to FIG. 8;

FIG. 10 is a view similar -to FIG. 8 showing the chair in a complete trandillenberg position;

FIG. 11 is a view similar to FIG. 8 wherein the chair is in a complete horizontal position;

FIG. 12 is a vertical cross sectional view as seen along the line 1212 in FIG. 3;

FIG. 13 is a fragmentary cross sectional view similar to FIG. 12 and showing the back rest unit in a changed position; and

FIG. 14 is in enlarged, detail side elevational view of a limit switch arrangement shown generally in FIG. 12.

Referring now to the drawings, the dental chair of this invention is indicated generally at 20 in FIG. 1 and is shown mounted on a vertically adjustable base 21 of a usual construction. The principal elements of the chair include a seat and leg unit 22, a back rest unit 23 pivotally connected at its lower end to the seat and leg unit 22, and an arm rest unit 24 interconnected between the units 22 and 23.

The seat and leg unit 22, hereinafter referred to as the seat unit for convenience, comprises an elongated wooden frame 26 (FIG. 3) of a rectangular shape in plan view and having, in side elevation, an upwardly facing, concavcly curved seat portion 27 integral with a straight leg portion 28. The seat frame 26 is reinforced by a transverse wooden member 29 (FIGS. 3 and 12) and by a rectangularly shaped metal member 31. The member 31 includes a pair of flat side plates 32 (FIGS. 3 and 12) curved to fit the contour of the sides 33 of the curved seat portion 27 to which they are secured, a gusseted end plate 34 located centrally of the frame 26 (FIG. 3) and extended transversely thereacross, and another end plate 36 extended across the frame 26 adjacent the back rest unit 23.

The seat frame 26 is tiltably mounted on a V-shaped casting 37 provided with depending side flanges 38 (FIG. 12) having journals through which pivot bolts 39 are threaded into the side plates 32 of the frame member 31. The casting 37 is rigidly secured to the upper end of the base 21 by means of suitable brackets or adapters (not shown) and includes a forward, inwardly tapered flanged portion 41 (FIGS. 4 and 12) at the front end of which a threaded block 42 is pivotally mounted for movement about a horizontal axis. Below the block, a ball bearing nut 43 is threadingly engaged with the pivot block 42.

For operative association with the casting 32 and the frame 26, a jack screw assembly 44 is provided. The assembly 44 includes a gear box 46 (FIG. 4) mounted substantially transversely central of the frame 26 on the gusseted end plate 34. A screw 47 is connected at its upper end to the gear box 46 by a universal joint 48, the lower end of the screw 47 being extended through the block 42 and threaded into the ball nut 43. A stop member 45 is secured to the lower end of the screw 47 to limit the upward movement of the screw in the ball nut, 43. By this arrangement, as will be clarified hereinafter, the seat unit 22 is tiltable relative to the casting 37 about a horizontal axis extended through the pivot bolts 39.

The back rest unit 23, pivotally mounted on the seat unit 22 for movement relative thereto, comprises an inverted U-shaped wooden frame 49 (FIGS. 3 and 4) the sides 51 of which are spaced wider apart at their bottom than at their top, whereby the width of the back frame 49 tapers inwardly from the bottom to the top thereof. An H-shaped reinforcing plate 52 is secured to the front side of the back frame 49 and has integral therewith a transverse member 53 rearwardly flanged to form a yoke 54 (FIG. 7) for pivotally mounting a block 56 and ball nut 57 as an assembly. The base of the plate 52 is reinforced by a transverse brace 58 (FIGS. 3 and 7) and directly thereabove a pivot bolt 59 (FIGS. 3 and 12) is journaled through the base of each. back frame side 51 and threaded into the rear end 61 of each side plate 32.

Integral with the plate 36 and extended rearwardly therefrom in the form of a yoke, are a pair of short arms 62 (FIGS. 7 and 12). An elongated bracket 63 has flanged portions 64 pivotally connected to the outer ends of the arms 62 and has mounted thereon a gear box 66 of a jack screw assembly 67 for the back unit 23. The assembly 67, in addition to the gear box 66 and the pivot block 56 and ball nut 57 (FIG. 7), includes a screw 68 threaded through the ball nut 57 and driven via a coupling 69 from the gear box 66. The coupling 69 connects the screw 68 with a shaft 71 which depends from the gear box 66 axially with the screw 68 and is rotatably mounted in a double thrust bearing 72 pivotally connected between the braces 62. A cap 73 is secured at the upper end of the screw 68 to limit rotation of the screw 68 downwardly through the ball nut 57. By this arrangement, operation of the jack screw assembly 67 causes the back unit 23 to pivot about the pivot bolts 59 and relative to the seat unit 22.

During movement of the back unit 23 relative to the seat unit 22, the arm rest unit 24 (FIG. 3) is arranged to maintain the arms of the patient substantially parallel with his legs whereby to maintain a comfortable position of the arms at all times irrespective of the relative positions of the seat and back units. The arm rest unit 24 includes a pair of rods 74 and 76, each of which has a lateral portion 77 journaled into and through a side 51 (FIG. 3) of the back frame 49, an intermediate portion 78 depending angularly from the portion 77, and an end portion 79 extending forwardly from the intermediate portion 78 at an obtuse angle therefrom (FIG. 12). Wooden arm supports 81 are aifixed to the end portions 79 of the rods 74 and 76.

The inner end of one rod portion 77 is secured by an allen lock 82 (FIG. 4) to a shaft end of a spring clutch assembly 83 to which the inner end of the other rod portion 77 is connected. By this arrangement, the rod 74 is raisable from a first position wherein the supports 81 are horizontally aligned as indicated by the full line showing in FIG. 4, to a second position in a vertical plane as indicated by the dotted line showing of the rod 74 in FIG. 4. As the lock 82 is mounted between a side of the plate 52 and a strut 80 (FIG. 3), it is prevented from lateral movement so as to maintain the rod 76 in position during operation of the spring clutch 83. Thus. a patient may readily and comfortably get into or out of the chair 20 from one side thereof.

,7 The arm rest unit 24 is completed by an irregular shaped connecting member 84 pivotally connected at its upper end to the front end of the rod 76 (FIG. 12). The lower end of the member 84 is of a U-shape and extends about the lower end of a side 33 of the seat frame 26, the upper end 86 (FIGS. 12 and 14) being pivotally connected to the side 33, as by a pin 87. The dimensioning and angular relation of the components of the arm rest unit 24 provides, that should the back unit 23 be pivoted rearwardly or forwardly from the position indicated in FIG. 12, the arm supports 81 will remain substantially parallel and transversely aligned (see FIG. 13). Furthermore, the structure of the arm rest unit 24 provides as best illustrated in FIGS. 8-11, inclusive, that irrespective of the relatively moved positions of the seat and leg unit 22 and the back rest unit 23, the arm supports 81 are always in a position to comfortably support the arms of the patient. Putting it another way, when the back test unit 23 pivots b'ackwardly and downwardly from the conventional position thereof as shown in FIG. 8, the arm supports 81 not only are maintained transversely parallel and aligned, but they also move rearwardly and are lowered relative to the seat and leg unit 22 to accommodate the changed position of the arms of the patient. Thus, upon movement of either seat and leg unit 22 or back rest unit 23, the arm rest unit is responsively moved accordingly.

As described hereinbefore, the seat unit frame 26 is tiltable relative to the fixed casting 37 by operation of the jack screw assembly 44 (FIG. 12), and the back unit frame 49 is pivotal relative to the seat unit frame by operation of the other second jack screw assembly 67 (FIG. 12). To power these assemblies 44 and 67, a pair of reversible electric motors 88 and 89 are provided. One motor 88 (FIG. 3) is assembled as a unit with the gear box 46 for the first jack screw assembly 44, and the other motor 89 is assembled as a unit with the gear box 66 (FIG. 3) for the second jack screw assembly 67.

The motors 88 and 89 are controlled by a circuit illustrated in FIG. 5 wherein they are placed in parallel for control by a pair of toggle switches 91 and 92, respectively. To limit the movement of the seat and back units 22 and 23, it will be noted that pairs 93a and 93b and of 94a and 94b of limiting switches are provided for the respective motors 88 and 89. The switches are of a conventional micro-type, maintained normally closed by a spring bias and are operable to break their particular circuit by pressure sufiicient to overcome the spring bias. The first pair of micro limit switches 93a and 93b are mounted individually on a side plate 32 (FIG. 12) of the seat frame member 31 for coaction, through corresponding spring-biased plungers 96, with a pair of stop elements 97 securely mounted to the bot tom side of the stationary casting 37.

By this arrangement, should the toggle switch 91 (FIG. 5) be closed to the contact 90, with the switch 93a normally closed, the motor 88 will operate through. the gear box 46 (FIG. 4) to actuate the jack screw assembly 44 so as to move the seat frame 26 in a clockwise pivotal direction (FIG. 12). This movement will continue until the rear switch 93a contacts the rear stop member 97, thereby depressing the plunger 96 to open the circuit and stop the motor 88. To reverse the motor drive so as to operate the jack screw assembly 45 to tilt the seat frame 26 in a counterclockwise direction (FIG. 12), thus raising the front thereof, the toggle switch 91 is moved to engage the contact (FIG. 5). As the frame 26 pivots, the rear stop member 97 moves upwardly and away from the switch 9311 thus permitting it to close again, the frame 26 continuing to pivot until the front switch 93b engages the front stop member 97 (FIG. 12), thereby opening the motor circuit.

The other pair of switches 94a and 94b are mounted on a bracket 98 (FIGS. 12 and 14) secured to the bottom of the casting 37, and also include plungers 99 adapted for coaction with a pair of stop members 101 secured to a block 102 mounted on the arm rest unit connecting member 84, best illustrated in FIG. 14. Thus, it may be readily seen that when the back frame 49 is in its forward or vertical position (FIG. 12) the connecting member 84 is also in a vertical position, as indicated in full lines in FIG. 14, whereby the rear stop 101 and the plunger 99 of the rear switch 94a are engaged to disconnect and open the switch 94a, thus breaking the circuit to the back frame motor 89.

In this position, the back frame 49 is prevented from further forward or clockwise pivotal movement (FIG. 12), but may be pivoted counterclockwise by moving the toggle switch 92 to engage a contact 103 (FIG. 5), whereby to reverse the motor 89 to operate through the gear box 66 (FIG. 3) the back unit jack screw assembly 67. The back frame 49 will continue to pivot rearwardly until the connecting member 84 reaches the inclined position indicated in dotted lines in FIG. 14, and indicative of the inclined position of the back frame 49 in FIG. 13, whereat the front stop 101 (FIG. 14) depresses the plunger 99 of the front switch 94b to open that switch and the circuit to the motor 89.

As an added feature of the dental chair 20, a vibrating motor 104 (FIGS. 3, 4 and 12) is mounted by a bracket 106 on the rear of the transverse wood member 29 for the seat frame 26. The motor 104 is placed in parallel with the other motors 88 and 89 in the circuit (FIG. 5) and is controlled by a rheostat 107 and a switch 108. The rheostat 107 is secured to a bracket 109 (FIG. 4) mounted on one side 33 of the seat frame 26 for hand operation beneath the seat unit 22.

By placing the three switches 91, 92 and 108 (FIGS. 5 and 7) on a panel 111 secured to the upper rear of the back frame 49, it may readily be appreciated that quick and effortless control over the respective positions of the seat and the back frames 26 and 49 is provided for the dentist. Thus, by the actuation of either one or the other, or both of the switches 91 and 92 simultaneously, the chair is operated smoothly to adjust itself to the posture of the patient or to a position desired by the dentist. FIGS. 8 l1, inclusive, illustrate four moved positions of the chair, namely, What may be termed a conventional position in FIG. 8, a jack-knife position in FIG. 9, a trandillenberg position in FIG. 10, and a complete horizontal in FIG. 11. These positions are attainable by the seat frame 26 and the back frame 49 being moved either independently of the other or simultaneously relative to each other by operation of the control circuit.

In the assembly of the chair 20, it should be noted that the operating mechanism and the mechanical structures therefor, all described hereinbefore, are substantially eucased by and assembled within the dimensional confines of the two frames 26 and 49. Subsequent to such assembly, a plurality of flat Z-shaped springs 112 (FIG. 2) are stretched transversely across the surfaces of the frames 26 and 49 and secured to the sides thereof. Burlap 113 is then secured across the springs as a foundation for padding 114 in the form of foam rubber or the like. The padding 114 is then held in place by a covering 116 of vinyl material or the like tacked to the frames 26 and 49 in the usual manner. As noted on the rear of the chair 20 (FIG. 6) the vinyl covering 116 may be secured to the frame 49 in panel form for ease of assembly and disassembly. The arm supports 81 are also covered with foam rubber and vinyl.

The completely assembled chair 20 (FIG. 1) thus presents a dental chair having extremely fine or increment adjustability for both the seat and leg unit 22 and the back rest unit 23 by means of the electric motor-driven jack screw assemblies which are operable independently or simultaneously. The contour and lengths of the units 22 and 23 are such that the entire lower half of a patient, from the buttocks to and including the feet is supported in a generally straight plane, while the upper half of the patient, including the head, neck and shoulders, is also entirely supported. The tapered back rest unit 23 enables the dentist to stand or sit closely to the patient thereby providing a comfortable and maneuverable working position for the dentist.

To hold a patients head, there is provided an adjustable head rest unit 117 (FIGS. 1 and 6) which comprises an elongated strip 118 of material such as vinyl movably inserted between the rear side of the back rest unit 23 and a spring-biased bar 119 secured thereacross. A U- shaped headblock 121 of covered foam rubber or the like is secured to the front end of the strip 118, which is positioned on the front side of the unit 23, it being readily appreciated that the headblock 121 is slidable upwardly and downwardly on the surface of the back rest 23 to accommodate any size of patient. For the purpose of holding a napkin (not shown) between the patients head and the head rest, a strap 122 is connected at each end to the sides of the strip 118. Another feature comprises an extra amount of padding, indicated generally at 121 in FIGS. 1 and 2, to provide additional support in the kidney area of a patient.

In summation, the invention discloses a dental chair 20 comprised of a contoured leg and seat unit 22 and a contoured back rest 23 pivotally carried on the unit 22 for pivotal movement relative to, or for movement together with, the unit 22. In turn, the unit 22 is pivotally supported on the casting 37 which constitutes a built-in support or mounting plate for the chair 20. Combined power and mechanical structures for pivotally moving the units 22 and 23 are contained within the dimensional confines of the units 22 and 23 whereby the chair 20 is a complete assembly that is operable independently of the base 21, which may be of any desired type since it serves only to rigidly sufpport the casting 37 at an elevated position.

Although only one preferred embodiment of the invention has been disclosed herein, it is to be remembered that various modifications and alternate constructions may be made within the scope of the invention, as defined in the appended claims.

I claim:

1. A dental chair having a base and comprising, a seat and leg unit having an elongated frame substantially rectangular in plan, a plate member securely mounted on said base and pivotally connected at each side thereof to :said frame whereby said frame i tiltable about a horizontal axis relative to said base, said plate member having a portion thereof extended longitudinally of said frame, a threaded nut pivotally mounted to said portion, first power means mounted on said frame, first jack screw means operatively associated with said first power means and having a screw member threaded through said nut whereby operation of said first power means causes said frame to tilt relative to said base, a back rest uni-t having a frame one end of which is pivotally connected to one end of said seat and leg unit frame, a support member secured to said seat and leg unit frame adjacent 'said pivotal connection and having a threaded nut pivotally mounted therewith, second power means mounted on said back rest unit frame, second jack screw means operatively associated with said second power means and having a screw mem ber threaded through the nut I011 said support member whereby operation of said second power means causes said back rest unit frame to pivot relative to said seat and leg unit, and selectively operable means for simultaneously or independently operating said first and second power means.

2. A dental chair including a base, a mounting plate secured to said base, a seat and leg unit, pivot means supporting the seat and leg unit on the mounting plate for tilting movement about a horizontal axis, a back rest unit pivotally secured to the seat and leg unit for relative movement thereto, a first reversible electric power means supported solely on said seat and leg unit including a rotatable drive member, coacting portions on said drive member and mounting plate to provide, on rotation of said drive member, for tilting movement of said seat and leg unit relative to said mounting plate, said mounting plate, pivot means and rotatable drive member wifih the coacting portions constituting the sole mechanical connection between the said seat and leg unit and the base, a second reversible electric power means supported solely on said back rest unit and being operatively connected with said seat and leg unit for pivoting the back rest unit relative to the seat and leg unit, switch control means for said first and second power means, a pair of arm rest members positioned above said seat and leg unit at opposite sides thereof, each of said arm rest members having a lateral portion journaled into and through a side of the back rest unit, said lateral portions of said arms being releasably connected together and a link member pivotally connected to the seat and leg unit and to a first one of said arm rest members to cause movement of both said arm rest members in response to the pivotal movement of either said back rest unit or said seat and leg unit when the lateral arm portions are connected together, the second of said arm rest members being freely movable in the vertical plane when its lateral portion is disconnected from the lateral portion of said first arm rest member. 7

3. A dental chair attachable to a base comprising a seat and leg unit, a plate member mounted on said base, pivot means supporting the seat and leg unit on the plate member for tilting movement about a horizontal axis, a back rest unit pivotally connected to the seat and leg unit for movement relative thereto, a first reversible power means operatively connected with said seat and leg unit and with said plate member for tilting of the seat and leg unit relative to said plate member, a second reversible power means operatively connected with said back rest unit and with said seat and leg unit for pivoting the back rest unit relative to the seat and leg unit, control means for said first and second power means, a pair of arm rest members positioned above said seat and leg unit at opposite sides thereof, said arm rest members having lateral portions jonrnaled on said back rest unit and extended transversely of said back rest unit toward each other, means releasably connecting said lateral portions, and means pivotally connected to the seat and leg unit and to a first one of said arm rest members to cause movement of both said arm rest members in response to the pivotal movement of either said back rest hens being freely movable in an upright plane when the lateral portion thereof is disconnected from the lateral portion of said first arm rest member.

4. A dental chair for attachment to a base comprising a plate member mounted on said base, a seat and leg unit pivoted on said plate member for pivotal movement, a back rest unit pivotally oonnected to the seat and leg unit for movement relative thereto, a pair of arm rest members positioned above said seat and leg unit at 0pposite sides thereof, means on said back rest unit releasably connecting together said arm members, and means movably connected to the seat and leg unit and to a first one of said arm members to provide for the movement of both said arm rest members in upright planes in response to the pivotal movement of either said back rest unit or said seat and leg unit when the arm rest members are connected together, the second of said arm rest members being freely movable in an upright plane when disconnected from said first arm rest member.

References (Iited by the Examiner UNITED STATES PATENTS D. 186,104 9/59 Naughton 15-3 366,514 7/87 Scarritt et al. 297-323 1,111,685 9/14 Allison 297-327 1,428,462 9/22 Ward 5-62 1,543,612 6/25 Pascaud 297-328 2,172,063 9/39 Hara 297-313 2,172,941 9/39 Manning et al. 5-60 2,668,581 2/54 Luketa a- 297-330 2,672,917 3/ 54 Collura 297-327 2,682,916 7/54 Lauterbach 297-328 2,783,826 3/57 Haltenberger 297-361 2,884,047 4/59 Abbott 297-339 2,901,026 8/59 Thaden 297-349 FOREIGN PATENTS 131,060 4/29 Switzerland. 201,576 2/ 39 Switzerland.

FRANK B. SHERRY, Primary Examiner. 

1. A DENTAL CHAIR HAVING A BASE AND COMPRISING, A SEAT AND LEG UNIT HAVING AN ELONGATED FRAME SUBSTANTIALLY RECTANGULAR IN PLAN, A PLATE MEMBER SECURELY MOUNTED ON SAID BASE AND PIVOTALLY CONNECTED AT EACH SIDE THEREOF TO SAID FRAME WHEREBY SAID FRAME IS TILTABLE ABOUT A HORIZONTAL AXIS RELATIVE TO SAID BASE, SAID PLATE MEMBER HAVING A PORTION THEREOF EXTENDED LONGITUDINALLY OF SAID FRAME, A THREADED NUT PIVOTALLY MOUNTED TO SAID PORTION, FIRST POWER MEANS MOUNTED ON SAID FRAME, FIRST JACK SCREW MEANS OPERATIVELY ASSOCIATED WITH SAID FIRST POWER MEANS AND HAVING A SCREW MEMBER THREADED THROUGH SAID NUT WHEREBY OPERATION OF SAID FIRST POWER MEANS CAUSES SAID FRAME TO TILT RELATIVE TO SAID BASE, A BACK REST UNIT HAVING A FRAME ONE END OF WHICH IS PIVOTALLY CONNECTED TO ONE END OF SAID SEAT AND LEG UNIT FRAME, A SUPPORT MEMBER SE- 